Zoe asks Elmo to watch her pet rock Rocco for her, but he's too busy playing with Baby David to notice when the rock disappears. He tries to placate Zoe by giving her a new rock, then uses his memory to figure out where the rock went.

This program thoughtfully and thoroughly examines the history of nuclear weapons, the most destructive force ever invented.Filmed in Europe, Japan and the US, this documentary focuses on the continuing struggle of citizens, scientists and political leaders working to reduce or eliminate the atomic threatwhile...

This program thoughtfully and thoroughly examines the history of nuclear weapons, the most destructive force ever invented.Filmed in Europe, Japan and the US, this documentary focuses on the continuing struggle of citizens, scientists and political leaders working to reduce or eliminate the atomic threatwhile...

FRONTLINE explores and illuminates the critical issues of our times -- from business and health to social issues, politics and war. Since 1983, FRONTLINE has served as public television's flagship public affairs series.

FRONTLINE explores and illuminates the critical issues of our times -- from business and health to social issues, politics and war. Since 1983, FRONTLINE has served as public television's flagship public affairs series.